Question #81671

1 Answer
Mar 25, 2014

Answer:

The hydrogen bonds between the nitrogenous base pairs of DNA are strong dipole-dipole attractions. They hold the two strands of DNA together.

Explanation:

The nitrogenous bases in DNA are A (adenine), C (cytosine), G (guanidine), and T (thymine). Here are their structures:

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In each of these bases, the nitrogen of the secondary amine bonds to the deoxyribose in the backbone.

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DNA consists of two strands running in opposite directions. The hydrophobic nitrogenous bases are on the inside, hidden from water.

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Hydrogen bonds between the nitrogenous base hold the two strands of DNA together. These hydrogen bonds are base specific. That is, A (adenine) can form hydrogen bonds only with T (thymine). C (cytosine) can form hydrogen bonds only with G (guanine).

The thymine-adenine pair interacts through two hydrogen bonds. The cytosine-guanine pair interacts through three hydrogen bonds.

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